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Mu L, Yin X, Bai H, Li J, Qiu L, Zeng Q, Fu S, Ye J. Mannose-binding lectin suppresses macrophage proliferation through TGF-β1 signaling pathway in Nile tilapia. Front Immunol 2023; 14:1159577. [PMID: 37261343 PMCID: PMC10227430 DOI: 10.3389/fimmu.2023.1159577] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2023] [Accepted: 04/25/2023] [Indexed: 06/02/2023] Open
Abstract
Mannose-binding lectin (MBL) is a multifunctional pattern recognition molecule, which not only mediates the recognition of pathogenic microorganisms and their products, playing an important role in innate immune defense, but also participates in adaptive immune responses of mammalian. However, it's related immune mechanism remains limited, especially the regulation of cell proliferation in early vertebrates. In this study, OnMBL was found to bind to kidney macrophages (MФ) from Nile tilapia (Oreochromis niloticus). Interestingly, OnMBL was able to reduce the proliferation of activated-MФ by regulating the cell cycle, arresting a large number of cells in the G0/G1 phase, and increasing the probability of apoptosis. More importantly, we found that the inhibition of cell proliferation by OnMBL was closely related to the evolutionarily conserved canonical transforming growth factor-beta 1 (TGF-β1) signaling pathway. Mechanistically, OnMBL could significantly increase the expression of TGF-β1, activate and regulate the downstream Smad-dependent pathway to reduce the MФ proliferation, thereby maintaining cellular homeostasis in the body's internal environment. This study represents the first description regarding the regulatory mechanisms of the MBL on cell proliferation in teleost fish, which provides a novel perspective on the understanding of the multiple function and evolutionary origins of C-type lectins in the immune system.
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Affiliation(s)
- Liangliang Mu
- Guangzhou Key Laboratory of Subtropical Biodiversity and Biomonitoring, Institute of Modern Aquaculture Science and Engineering, School of Life Sciences, South China Normal University, Guangzhou, Guangdong, China
| | - Xiaoxue Yin
- Guangzhou Key Laboratory of Subtropical Biodiversity and Biomonitoring, Institute of Modern Aquaculture Science and Engineering, School of Life Sciences, South China Normal University, Guangzhou, Guangdong, China
| | - Hao Bai
- Guangzhou Key Laboratory of Subtropical Biodiversity and Biomonitoring, Institute of Modern Aquaculture Science and Engineering, School of Life Sciences, South China Normal University, Guangzhou, Guangdong, China
| | - Jiadong Li
- Guangzhou Key Laboratory of Subtropical Biodiversity and Biomonitoring, Institute of Modern Aquaculture Science and Engineering, School of Life Sciences, South China Normal University, Guangzhou, Guangdong, China
| | - Li Qiu
- Guangzhou Key Laboratory of Subtropical Biodiversity and Biomonitoring, Institute of Modern Aquaculture Science and Engineering, School of Life Sciences, South China Normal University, Guangzhou, Guangdong, China
| | - Qingliang Zeng
- Guangzhou Key Laboratory of Subtropical Biodiversity and Biomonitoring, Institute of Modern Aquaculture Science and Engineering, School of Life Sciences, South China Normal University, Guangzhou, Guangdong, China
| | - Shengli Fu
- Guangzhou Key Laboratory of Subtropical Biodiversity and Biomonitoring, Institute of Modern Aquaculture Science and Engineering, School of Life Sciences, South China Normal University, Guangzhou, Guangdong, China
| | - Jianmin Ye
- Guangzhou Key Laboratory of Subtropical Biodiversity and Biomonitoring, Institute of Modern Aquaculture Science and Engineering, School of Life Sciences, South China Normal University, Guangzhou, Guangdong, China
- Guangdong Provincial Engineering Technology Research Center for Environmentally-Friendly Aquaculture, School of Life Sciences, South China Normal University, Guangzhou, Guangdong, China
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Smolnikova MV, Tereshchenko SY. Proteins of the lectin pathway of the complement system activation: immunobiological functions, genetics and involvement in the pathogenesis of human diseases. RUSSIAN JOURNAL OF INFECTION AND IMMUNITY 2022. [DOI: 10.15789/2220-7619-pot-1777] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
The complement system is the most ancient components in the innate immunity, mainly functioning to primarily eliminate bacterial agents intravascularly. Moreover, the complement complex proteins play a role as a bridge between the systems of innate and adaptive immunity providing adequate conditions for maturation and differentiation of B- and T-lymphocytes. The complement system consists of plasma proteins and membrane receptors. Plasma proteins interact with each other via the three described cascade pathways lectin (which is most ancient phylogenetically), alternative and classical. Lectins are proteins comprising a separate superfamily of pattern-recognizing receptors able to sense molecules of oligo- and polysaccharide nature and induce their aggregation. Among all the lectins, ficolins (FCN) (common domain fibrinogen) and collectins (common domain collagen) mannose-binding lectin (MBL), hepatic and renal collectins have exert unique functions by complexing with carbohydrate components of microbial wall. Formation of a compound complex microbial wall polysaccharides + collectin/ficolin + specific mannose-binding lectin-associated serine proteases (MARP) results in the complement system activation, inflammatory reaction and bacterium elimination. Such scenario is proceeded along the lectin pathway compared to the two other pathways called classical and alternative. Examining a role of the complement system and congenital protein defects in the pathogenesis of various diseases is of topical interest because inborn deficiency of the complement components comprises at least 5% out of total primary immunodeficiency rate, whereas the aspects of their prevalence and pathogenesis remain unexplored. Relevance of investigating the complement system components for diverse populations is tremendous, taking into consideration accumulated evidence regarding an important role of the lectin pathway in viral infections. Lectins, the main proteins in the lectin pathway of the complement activation, are encoded by polymorphic genes, wherein single nucleotide polymorphisms (SNPs) result in altered protein conformation and expression, which, in turn, affects functionality and potential to respond to a pathogen. The distribution of the lectin polymorphic gene frequencies and their haplotypes displays extremely marked population differences. According to analyzing available data, population SNP frequencies including those associated with inborn deficiencies for components of the lectin pathway have been currently scarce or unexplored. hence, here we review major lectins and their functions, their functionally significant SNPs in diverse populations and their pathogenetic importance for host defense functions.
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Gytz Olesen H, Michailidou I, Zelek WM, Vreijling J, Ruizendaal P, de Klein F, Marquart JA, Kuipers TB, Mei H, Zhang Y, Ahasan M, Johnson KK, Wang Y, Morgan BP, van Dijk M, Fluiter K, Andersen GR, Baas F. Development, Characterization, and in vivo Validation of a Humanized C6 Monoclonal Antibody that Inhibits the Membrane Attack Complex. J Innate Immun 2022; 15:16-36. [PMID: 35551129 PMCID: PMC10643903 DOI: 10.1159/000524587] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2022] [Accepted: 03/08/2022] [Indexed: 11/19/2022] Open
Abstract
Damage and disease of nerves activates the complement system. We demonstrated that activation of the terminal pathway of the complement system leads to the formation of the membrane attack complex (MAC) and delays regeneration in the peripheral nervous system. Animals deficient in the complement component C6 showed improved recovery after neuronal trauma. Thus, inhibitors of the MAC might be of therapeutic use in neurological disease. Here, we describe the development, structure, mode of action, and properties of a novel therapeutic monoclonal antibody, CP010, against C6 that prevents formation of the MAC in vivo. The monoclonal antibody is humanized and specific for C6 and binds to an epitope in the FIM1-2 domain of human and primate C6 with sub-nanomolar affinity. Using biophysical and structural studies, we show that the anti-C6 antibody prevents the interaction between C6 and C5/C5b by blocking the C6 FIM1-2:C5 C345c axis. Systemic administration of the anti-C6 mAb caused complete depletion of free C6 in circulation in transgenic rats expressing human C6 and thereby inhibited MAC formation. The antibody prevented disease in experimental autoimmune myasthenia gravis and ameliorated relapse in chronic relapsing experimental autoimmune encephalomyelitis in human C6 transgenic rats. CP010 is a promising complement C6 inhibitor that prevents MAC formation. Systemic administration of this C6 monoclonal antibody has therapeutic potential in the treatment of neuronal disease.
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Affiliation(s)
- Heidi Gytz Olesen
- Department of Molecular Biology and Genetics - Protein Science, Aarhus University, Aarhus, Denmark
| | | | - Wioleta M Zelek
- Division of Infection and Immunity and Dementia Research Institute, Systems Immunity Research Institute, School of Medicine, Cardiff University, Cardiff, UK
| | | | | | - Ferry de Klein
- Core Facility Genomics, Amsterdam UMC, Amsterdam, The Netherlands
| | | | - Thomas B Kuipers
- Sequencing Analysis Support Core, Department of Biomedical Data Sciences, LUMC, Leiden, The Netherlands
| | - Hailiang Mei
- Sequencing Analysis Support Core, Department of Biomedical Data Sciences, LUMC, Leiden, The Netherlands
| | - Yuchun Zhang
- Alexion, AstraZeneca Rare Disease, New Haven, Connecticut, USA
| | - Muhammad Ahasan
- Alexion, AstraZeneca Rare Disease, New Haven, Connecticut, USA
| | | | - Yi Wang
- Alexion, AstraZeneca Rare Disease, New Haven, Connecticut, USA
| | - B Paul Morgan
- Division of Infection and Immunity and Dementia Research Institute, Systems Immunity Research Institute, School of Medicine, Cardiff University, Cardiff, UK
| | | | - Kees Fluiter
- Department of Clinical Genetics, LUMC, Leiden, The Netherlands,
| | - Gregers Rom Andersen
- Department of Molecular Biology and Genetics - Protein Science, Aarhus University, Aarhus, Denmark
| | - Frank Baas
- Department of Clinical Genetics, LUMC, Leiden, The Netherlands
- Complement Pharma BV, Amsterdam, The Netherlands
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Cortes C, Desler C, Mazzoli A, Chen JY, Ferreira VP. The role of properdin and Factor H in disease. Adv Immunol 2022; 153:1-90. [PMID: 35469595 DOI: 10.1016/bs.ai.2021.12.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The complement system consists of three pathways (alternative, classical, and lectin) that play a fundamental role in immunity and homeostasis. The multifunctional role of the complement system includes direct lysis of pathogens, tagging pathogens for phagocytosis, promotion of inflammatory responses to control infection, regulation of adaptive cellular immune responses, and removal of apoptotic/dead cells and immune complexes from circulation. A tight regulation of the complement system is essential to avoid unwanted complement-mediated damage to the host. This regulation is ensured by a set of proteins called complement regulatory proteins. Deficiencies or malfunction of these regulatory proteins may lead to pro-thrombotic hematological diseases, renal and ocular diseases, and autoimmune diseases, among others. This review focuses on the importance of two complement regulatory proteins of the alternative pathway, Factor H and properdin, and their role in human diseases with an emphasis on: (a) characterizing the main mechanism of action of Factor H and properdin in regulating the complement system and protecting the host from complement-mediated attack, (b) describing the dysregulation of the alternative pathway as a result of deficiencies, or mutations, in Factor H and properdin, (c) outlining the clinical findings, management and treatment of diseases associated with mutations and deficiencies in Factor H, and (d) defining the unwanted and inadequate functioning of properdin in disease, through a discussion of various experimental research findings utilizing in vitro, mouse and human models.
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Affiliation(s)
- Claudio Cortes
- Department of Foundational Medical Studies, Oakland University William Beaumont School of Medicine, Rochester, MI, United States.
| | - Caroline Desler
- Oakland University William Beaumont School of Medicine, Rochester, MI, United States
| | - Amanda Mazzoli
- Oakland University William Beaumont School of Medicine, Rochester, MI, United States
| | - Jin Y Chen
- Department of Inflammation and Immunity, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, United States
| | - Viviana P Ferreira
- Department of Medical Microbiology and Immunology, University of Toledo College of Medicine and Life Sciences, Toledo, OH, United States.
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Kalia N, Singh J, Kaur M. The ambiguous role of mannose-binding lectin (MBL) in human immunity. Open Med (Wars) 2021; 16:299-310. [PMID: 33681468 PMCID: PMC7917369 DOI: 10.1515/med-2021-0239] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2020] [Revised: 01/22/2021] [Accepted: 01/29/2021] [Indexed: 12/30/2022] Open
Abstract
Mannose-binding lectin (MBL) and lectin complement pathway have become targets of increasing clinical interest. Many aspects of MBL have been recently explored, including the structural properties that allow it to distinguish self from non-self/altered-self structures. Experimental evidences have declared the additional 5′- and 3′-variants that in amalgamation with well-known secretor polymorphisms change MBL function and concentration. Moreover, the current review highlights the differential behavior of MBL on exposure with extra/intracellular pathogens and in autoimmune diseases, stressing the fact that “high MBL levels can increase diseases susceptibility,” a paradox that needs justification. Attributable to these discrepancies, no absolute level of MBL deficiency could be defined so far and thus must be interpreted for specific diseases through case–control population-specific designs. Overall, it is evident that further research is needed about MBL and the lectin pathway of complement. Particularly, the transformative role of MBL over evolution is of interest and its role with regard to pathogenesis of different diseases and potential therapeutic targets within the respective pathways should be further explored. Apart from this, it is necessary to adopt an extensive locus-wide methodology to apprehend the clinical significance of MBL2 polymorphisms in a variety of infectious diseases by the future studies.
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Affiliation(s)
- Namarta Kalia
- Department of Molecular Biology and Biochemistry, Guru Nanak Dev University, Amritsar, India.,Department of Biological Sciences, George Washington University, Washington, DC 20052, USA
| | - Jatinder Singh
- Department of Molecular Biology and Biochemistry, Guru Nanak Dev University, Amritsar, India
| | - Manpreet Kaur
- Department of Human Genetics, Guru Nanak Dev University, Amritsar, India
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Willmann EA, Pandurovic V, Jokinen A, Beckley D, Bohlson SS. Extracellular signal-regulated kinase 1/2 is required for complement component C1q and fibronectin dependent enhancement of Fcγ- receptor mediated phagocytosis in mouse and human cells. BMC Immunol 2020; 21:61. [PMID: 33317446 PMCID: PMC7734837 DOI: 10.1186/s12865-020-00393-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2020] [Accepted: 12/02/2020] [Indexed: 11/25/2022] Open
Abstract
Background C1q is a soluble pattern recognition protein that regulates multiple leukocyte functions, and deficiency in C1q results in autoimmunity. C1q stimulates enhanced phagocytic function through multiple mechanisms including the rapid enhancement of Fcγ receptor (FcγR) -mediated phagocytosis. The molecular mechanism responsible for this rapid enhancement of phagocytic function is unknown. The purpose of this study was to investigate the molecular pathway required for C1q-dependent enhanced phagocytosis. Results Leukocyte associated immunoglobulin like receptor-1 (LAIR-1) is a receptor that mediates C1q-dependent activation of leukocytes; however, using LAIR-1 deficient mouse bone marrow derived macrophages (BMDM), we demonstrated that LAIR-1 was not required for C1q-dependent enhanced FcγR-mediated phagocytosis. A phospho-kinase array identified extracellular signal-regulated kinase (ERK) 1/2 as dysregulated following activation with C1q. Validation of the array in BMDM and the human monocyte cell line THP-1 demonstrated a decrease in basal ERK1/2 phosphorylation in C1q-stimulated cells compared to control cells. However, subsequent stimulation with immune complexes stimulated rapid upregulation of phosphorylation. The extracellular matrix protein fibronectin regulates enhanced phagocytic activity in macrophages similar to C1q, and both C1q and fibronectin-dependent enhanced phagocytosis required ERK1/2 since both were blocked by pharmacologic inhibition of ERK1/2. Furthermore, diminished C1q-dependent ERK1/2 phosphorylation was sustained after four-hour treatment with lipopolysaccharide and correlated with a significant reduction in TNFα production. Conclusions These data demonstrate that C1q and fibronectin utilize a similar ERK1/2-dependent mechanism for enhanced phagocytosis, which should lead to development of novel approaches to modulate C1q-dependent regulation of macrophage activation, inflammation and autoimmunity. Supplementary Information The online version contains supplementary material available at 10.1186/s12865-020-00393-6.
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Affiliation(s)
- Emily A Willmann
- Department of Microbiology and Immunology, Des Moines University, Des Moines, IA, USA
| | - Vesna Pandurovic
- Department of Microbiology and Immunology, Des Moines University, Des Moines, IA, USA
| | - Anna Jokinen
- Department of Microbiology and Immunology, Des Moines University, Des Moines, IA, USA
| | - Danielle Beckley
- Department of Microbiology and Immunology, Des Moines University, Des Moines, IA, USA
| | - Suzanne S Bohlson
- Department of Molecular Biology and Biochemistry, University of California, Irvine, CA, USA.
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Mu L, Yin X, Wu H, Lei Y, Han K, Mo J, Guo Z, Li J, Ye J. Mannose-Binding Lectin Possesses Agglutination Activity and Promotes Opsonophagocytosis of Macrophages with Calreticulin Interaction in an Early Vertebrate. THE JOURNAL OF IMMUNOLOGY 2020; 205:3443-3455. [PMID: 33199536 DOI: 10.4049/jimmunol.2000256] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/09/2020] [Accepted: 10/15/2020] [Indexed: 12/18/2022]
Abstract
The innate immune system is an ancient defense system in the process of biological evolution, which can quickly and efficiently resist pathogen infection. In mammals, mannose-binding lectin (MBL) is a key molecule in the innate immune and plays an essential role in the first line of host defense against pathogenic bacteria. However, the evolutionary origins and ancient roles of immune defense of MBL and its mechanism in clearance of microbial pathogens are still unclear, especially in early vertebrates. In this study, Oreochromis niloticus MBL (OnMBL) was successfully isolated and purified from the serum of Nile tilapia (O. niloticus). The OnMBL was able to bind and agglutinate with two important pathogens of tilapia, Streptococcus agalactiae and Aeromonas hydrophila Interestingly, the OnMBL was able to significantly inhibit the proliferation of pathogenic bacteria and reduce the inflammatory response. Upon bacterial challenge, the downregulation of OnMBL expression by RNA interference could lead to rapid proliferation of the pathogenic bacteria, ultimately resulting in tilapia death. However, the phenotype was rescued by reinjection of the OnMBL, which restored the healthy status of the knockdown tilapia. Moreover, a mechanistic analysis revealed that the OnMBL could clear pathogenic bacteria by collaborating with cell-surface calreticulin to facilitate phagocytosis in a complement activation-independent manner. To our knowledge, these results provide the first evidence on the antibacterial response mechanism of MBL performing evolutionary conserved function to promote opsonophagocytosis of macrophages in early vertebrates and reveals new insights into the understanding of the evolutionary origins and ancient roles basis of the C-type lectins in the innate immune defense.
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Affiliation(s)
- Liangliang Mu
- Guangdong Provincial Key Laboratory for Healthy and Safe Aquaculture, Institute of Modern Aquaculture Science and Engineering, School of Life Sciences, South China Normal University, Guangdong 510631, People's Republic of China; and
| | - Xiaoxue Yin
- Guangdong Provincial Key Laboratory for Healthy and Safe Aquaculture, Institute of Modern Aquaculture Science and Engineering, School of Life Sciences, South China Normal University, Guangdong 510631, People's Republic of China; and
| | - Hairong Wu
- Guangdong Provincial Key Laboratory for Healthy and Safe Aquaculture, Institute of Modern Aquaculture Science and Engineering, School of Life Sciences, South China Normal University, Guangdong 510631, People's Republic of China; and
| | - Yang Lei
- Guangdong Provincial Key Laboratory for Healthy and Safe Aquaculture, Institute of Modern Aquaculture Science and Engineering, School of Life Sciences, South China Normal University, Guangdong 510631, People's Republic of China; and
| | - Kailiang Han
- Guangdong Provincial Key Laboratory for Healthy and Safe Aquaculture, Institute of Modern Aquaculture Science and Engineering, School of Life Sciences, South China Normal University, Guangdong 510631, People's Republic of China; and
| | - Jinfeng Mo
- Guangdong Provincial Key Laboratory for Healthy and Safe Aquaculture, Institute of Modern Aquaculture Science and Engineering, School of Life Sciences, South China Normal University, Guangdong 510631, People's Republic of China; and
| | - Zheng Guo
- Guangdong Provincial Key Laboratory for Healthy and Safe Aquaculture, Institute of Modern Aquaculture Science and Engineering, School of Life Sciences, South China Normal University, Guangdong 510631, People's Republic of China; and
| | - Jun Li
- School of Science and Medicine, Lake Superior State University, Sault Ste. Marie, MI 49783
| | - Jianmin Ye
- Guangdong Provincial Key Laboratory for Healthy and Safe Aquaculture, Institute of Modern Aquaculture Science and Engineering, School of Life Sciences, South China Normal University, Guangdong 510631, People's Republic of China; and
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8
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Mao F, Liu K, Bao Y, Lin Y, Zhang X, Xu D, Xiang Z, Li J, Zhang Y, Yu Z. Opsonic character of the plasma proteins in phagocytosis-dependent host response to bacterial infection in a marine invertebrate, Crassostrea gigas. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2020; 106:103596. [PMID: 31877328 DOI: 10.1016/j.dci.2019.103596] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/26/2019] [Revised: 12/20/2019] [Accepted: 12/21/2019] [Indexed: 06/10/2023]
Abstract
Phagocytosis is an evolutionarily conserved immune response, whose efficiency is fundamentally coupled with opsonization of extracellular microbes. How marine mollusks cells recognize and selectively capture pathogens during phagocytosis to clear them is not completely understood. In this study, we observed that plasma is extremely effective for oyster hemocyte phagocytosis, so we investigated candidate proteins among plasma proteins with binding affinity for Vibrio parahaemolyticus in Pacific oyster (Crassostrea gigas) by subjecting them to mass spectroscopy analysis for protein identification and characterization, and address the complex regulatory network to engulf invaders. There were 620 identified proteins potentially associated with bacteria binding and phagocytosis which could be quantified. Our results showed that C1q and lectins identified in Pacific oyster plasma held binding ability to bacteria, clearly suggesting their potent to be opsonins. The dominant expressed plasma protein p1-CgC1q (Complement component 1q)-like protein was identified and its opsonic role was confirmed in this study. The cell surface receptor Cgintegrin interacts directly with p1-CgC1q to mediate phagocytosis. We further confirmed that the interaction between C1q and integrin not rely on the typical recognition site RGD but on the RGE. Evidence exist revealed that p1-CgC1q could coat bacteria via the endotoxin LPS (lipopolysaccharide) and subsequently bind the receptor integrin to significantly enhance hemocytic phagocytosis and bacteria clearance. This study has thus furnished clear evidence for the importance of plasma proteins in mollusk, shedding light on the humoral immunity and an underappreciated strategy in marine host-pathogen interactions.
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Affiliation(s)
- Fan Mao
- Key Laboratory of Tropical Marine Bio-resources and Ecology, Guangdong Provincial Key Laboratory of Applied Marine Biology, South China Sea Institute of Oceanology, Chinese Academy of Science, Guangzhou, 510301, China; Innovation Academy of South China Sea Ecology and Environmental Engineering, Chinese Academy of Sciences, Guangzhou, 510301, China; Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou, 510301, China
| | - Kunna Liu
- Key Laboratory of Tropical Marine Bio-resources and Ecology, Guangdong Provincial Key Laboratory of Applied Marine Biology, South China Sea Institute of Oceanology, Chinese Academy of Science, Guangzhou, 510301, China; Innovation Academy of South China Sea Ecology and Environmental Engineering, Chinese Academy of Sciences, Guangzhou, 510301, China; University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Yongbo Bao
- Zhejiang Key Laboratory of Aquatic Germplasm Resources, College of Biological and Environmental Sciences, Zhejiang Wanli University, Ningbo, 315100, China
| | - Yue Lin
- Key Laboratory of Tropical Marine Bio-resources and Ecology, Guangdong Provincial Key Laboratory of Applied Marine Biology, South China Sea Institute of Oceanology, Chinese Academy of Science, Guangzhou, 510301, China; Innovation Academy of South China Sea Ecology and Environmental Engineering, Chinese Academy of Sciences, Guangzhou, 510301, China; University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Xiangyu Zhang
- Key Laboratory of Tropical Marine Bio-resources and Ecology, Guangdong Provincial Key Laboratory of Applied Marine Biology, South China Sea Institute of Oceanology, Chinese Academy of Science, Guangzhou, 510301, China; Innovation Academy of South China Sea Ecology and Environmental Engineering, Chinese Academy of Sciences, Guangzhou, 510301, China; University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Duo Xu
- Key Laboratory of Tropical Marine Bio-resources and Ecology, Guangdong Provincial Key Laboratory of Applied Marine Biology, South China Sea Institute of Oceanology, Chinese Academy of Science, Guangzhou, 510301, China; Innovation Academy of South China Sea Ecology and Environmental Engineering, Chinese Academy of Sciences, Guangzhou, 510301, China; University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Zhiming Xiang
- Key Laboratory of Tropical Marine Bio-resources and Ecology, Guangdong Provincial Key Laboratory of Applied Marine Biology, South China Sea Institute of Oceanology, Chinese Academy of Science, Guangzhou, 510301, China; Innovation Academy of South China Sea Ecology and Environmental Engineering, Chinese Academy of Sciences, Guangzhou, 510301, China; Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou, 510301, China
| | - Jun Li
- Key Laboratory of Tropical Marine Bio-resources and Ecology, Guangdong Provincial Key Laboratory of Applied Marine Biology, South China Sea Institute of Oceanology, Chinese Academy of Science, Guangzhou, 510301, China; Innovation Academy of South China Sea Ecology and Environmental Engineering, Chinese Academy of Sciences, Guangzhou, 510301, China; Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou, 510301, China
| | - Yang Zhang
- Key Laboratory of Tropical Marine Bio-resources and Ecology, Guangdong Provincial Key Laboratory of Applied Marine Biology, South China Sea Institute of Oceanology, Chinese Academy of Science, Guangzhou, 510301, China; Innovation Academy of South China Sea Ecology and Environmental Engineering, Chinese Academy of Sciences, Guangzhou, 510301, China; Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou, 510301, China.
| | - Ziniu Yu
- Key Laboratory of Tropical Marine Bio-resources and Ecology, Guangdong Provincial Key Laboratory of Applied Marine Biology, South China Sea Institute of Oceanology, Chinese Academy of Science, Guangzhou, 510301, China; Innovation Academy of South China Sea Ecology and Environmental Engineering, Chinese Academy of Sciences, Guangzhou, 510301, China; Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou, 510301, China.
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9
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Parker SE, Hanton AM, Stefanou SN, Noakes PG, Woodruff TM, Lee JD. Revisiting the role of the innate immune complement system in ALS. Neurobiol Dis 2019; 127:223-232. [DOI: 10.1016/j.nbd.2019.03.003] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2018] [Revised: 02/21/2019] [Accepted: 03/04/2019] [Indexed: 12/11/2022] Open
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10
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Blackburn JWD, Lau DHC, Liu EY, Ellins J, Vrieze AM, Pawlak EN, Dikeakos JD, Heit B. Soluble CD93 is an apoptotic cell opsonin recognized by α x β 2. Eur J Immunol 2019; 49:600-610. [PMID: 30656676 DOI: 10.1002/eji.201847801] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2018] [Revised: 12/13/2018] [Accepted: 01/16/2019] [Indexed: 11/11/2022]
Abstract
Efferocytosis is essential for homeostasis and prevention of the inflammatory and autoimmune diseases resulting from apoptotic cell lysis. CD93 is a transmembrane glycoprotein previously implicated in efferocytosis, with mutations in CD93 predisposing patients to efferocytosis-associated diseases. CD93 is a cell surface protein, which is proteolytically shed under inflammatory conditions, but it is unknown how CD93 mediates efferocytosis or whether its efferocytic activity is mediated by the soluble or membrane-bound form. Herein, using cell lines and human monocytes and macrophages, we demonstrate that soluble CD93 (sCD93) potently opsonizes apoptotic cells but not a broad range of microorganisms, whereas membrane-bound CD93 has no phagocytic, efferocytic, or tethering activity. Using mass spectrometry, we identified αx β2 as the receptor that recognizes sCD93, and via deletion mutagenesis determined that sCD93 binds to apoptotic cells via its C-type lectin-like domain and to αx β2 by its EGF-like repeats. The bridging of apoptotic cells to αx β2 markedly enhanced efferocytosis by macrophages and was abrogated by αx β2 knockdown. Combined, these data elucidate the mechanism by which CD93 regulates efferocytosis and identifies a previously unreported opsonin-receptor system utilized by phagocytes for the efferocytic clearance of apoptotic cells.
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Affiliation(s)
- Jack W D Blackburn
- Department of Microbiology and Immunology, Center for Human Immunology, The University of Western Ontario, London, Ontario, Canada
| | - Darius H C Lau
- Department of Microbiology and Immunology, Center for Human Immunology, The University of Western Ontario, London, Ontario, Canada
| | - Elaine Y Liu
- Department of Microbiology and Immunology, Center for Human Immunology, The University of Western Ontario, London, Ontario, Canada
| | - Jessica Ellins
- Department of Microbiology and Immunology, Center for Human Immunology, The University of Western Ontario, London, Ontario, Canada
| | - Angela M Vrieze
- Department of Microbiology and Immunology, Center for Human Immunology, The University of Western Ontario, London, Ontario, Canada
| | - Emily N Pawlak
- Department of Microbiology and Immunology, Center for Human Immunology, The University of Western Ontario, London, Ontario, Canada
| | - Jimmy D Dikeakos
- Department of Microbiology and Immunology, Center for Human Immunology, The University of Western Ontario, London, Ontario, Canada
| | - Bryan Heit
- Department of Microbiology and Immunology, Center for Human Immunology, The University of Western Ontario, London, Ontario, Canada
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Szebeni J, Bedőcs P, Dézsi L, Urbanics R. A porcine model of complement activation-related pseudoallergy to nano-pharmaceuticals: Pros and cons of translation to a preclinical safety test. PRECISION NANOMEDICINE 2018. [DOI: 10.29016/180427.1] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Pigs provide a sensitive and quantitative animal model of non-IgE-mediated(pseudoallergic) hypersensitivity reactions (HSRs) caused by liposomes and many other nanoparticulate drugs or drug-carrier nanosystems (nanomedicines). The rapidly arising symptoms, including cardiopulmonary, hemodynamic, hematological, blood chemistry and skin changes, resemble the clinical picture in man undergoing infusion reactions toreactogenic nanoparticles. In addition to summarizing the basic features of the pig CARPA model, thereviewconsiderssome of the advantages and disadvantages of using the modelforpreclinical evaluation of nanomedicine safety.
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Affiliation(s)
- János Szebeni
- Nanomedicine Research and Education Center, Semmelweis University, Budapest, Hungary
| | - Péter Bedőcs
- Uniformed Services University of the Health Sciences, Bethesda, MD, USA
| | - László Dézsi
- Nanomedicine Research and Education Center, Semmelweis University, Budapest, Hungary
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12
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Alawieh A, Tomlinson S. Injury site-specific targeting of complement inhibitors for treating stroke. Immunol Rev 2017; 274:270-280. [PMID: 27782326 DOI: 10.1111/imr.12470] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Cumulative evidence indicates a role for the complement system in both pathology and recovery after ischemic stroke. Here, we review the current understanding of the dual role of complement in poststroke injury and recovery, and discuss the challenges of anti-complement therapies. Most complement directed therapeutics currently under investigation or development systemically inhibit the complement system, but since complement is important for immune surveillance and is involved in various homeostatic activities, there are potential risks associated with systemic inhibition. Depending on the target within the complement pathway, other concerns are high concentrations of inhibitor required, low efficacy and poor bioavailability. To overcome these limitations, approaches to target complement inhibitors to specific sites have been investigated. Here, we discuss targeting strategies, with a focus on strategies developed in our lab, to specifically localize complement inhibition to sites of tissue injury and complement activation, and in particular to the postischemic brain. We discuss various injury site-specific targeted complement inhibitors as potential therapeutic agents for the treatment of ischemic stroke treatment, as well as their use as investigative tools for probing complement-dependent pathophysiological processes.
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Affiliation(s)
- Ali Alawieh
- Medical Scientist Training Program, Medical University of South Carolina, Charleston, SC, USA.,Department of Microbiology and Immunology, Children's Research Institute, Medical University of South Carolina, Charleston, SC, USA
| | - Stephen Tomlinson
- Department of Microbiology and Immunology, Children's Research Institute, Medical University of South Carolina, Charleston, SC, USA. .,Ralph H. Johnson Veteran Affairs Medical Center, Charleston, SC, USA.
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Thielens NM, Tedesco F, Bohlson SS, Gaboriaud C, Tenner AJ. C1q: A fresh look upon an old molecule. Mol Immunol 2017; 89:73-83. [PMID: 28601358 DOI: 10.1016/j.molimm.2017.05.025] [Citation(s) in RCA: 139] [Impact Index Per Article: 19.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2017] [Revised: 05/27/2017] [Accepted: 05/29/2017] [Indexed: 12/14/2022]
Abstract
Originally discovered as part of C1, the initiation component of the classical complement pathway, it is now appreciated that C1q regulates a variety of cellular processes independent of complement activation. C1q is a complex glycoprotein assembled from 18 polypeptide chains, with a C-terminal globular head region that mediates recognition of diverse molecular structures, and an N-terminal collagen-like tail that mediates immune effector mechanisms. C1q mediates a variety of immunoregulatory functions considered important in the prevention of autoimmunity such as the enhancement of phagocytosis, regulation of cytokine production by antigen presenting cells, and subsequent alteration in T-lymphocyte maturation. Furthermore, recent advances indicate additional roles for C1q in diverse physiologic and pathologic processes including pregnancy, tissue repair, and cancer. Finally, C1q is emerging as a critical component of neuronal network refinement and homeostatic regulation within the central nervous system. This review summarizes the classical functions of C1q and reviews novel discoveries within the field.
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Affiliation(s)
| | - Francesco Tedesco
- Istituto di Ricovero e Cura a Carattere Scientifico, Istituto Auxologico Italiano, Milan, Italy
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14
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Dzwonek AB, Woźniakowska-GĘsicka T, Wiśniewska-Ligier M. Mannose-binding lectin in chronic hepatitis C in children. Scand J Gastroenterol 2016; 50:1276-84. [PMID: 25956563 DOI: 10.3109/00365521.2015.1006673] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
OBJECTIVE To investigate effect of mannose-binding lectin (MBL) genetic polymorphisms and phenotype in chronic hepatitis C and its impact on response to antiviral therapy in children. METHODS Fifty four children with chronic hepatitis C, aged 2.5-18 years were enrolled. Forty-five children were treated with interferon-α (IFN-α) alone (n = 2) or IFN-α and ribavirin (n = 43). Twenty-one children who responded to antiviral therapy were defined as sustained responders to therapy (IFN-SR). Before therapy, MBL genotypes and serum MBL levels (by ELISA) were determined. MBL genotype distribution and levels were correlated to disease characteristics and response to therapy. RESULTS Children with chronic hepatitis C who did not respond to antiviral therapy (IFN-NR) presented more frequently MBL2 polymorphisms, although this did not reach significance (p = 0.08). MBL levels were significantly lower in children classified as IFN-NR when compared to children defined as IFN-SR (1.623 ng/ml vs. 3.699 ng/ml), (p = 0.04). Serum activity levels of ALT and AST were higher in children with A/O MBL genotype when compared to group with A/A genotype (p < 0.05). CONCLUSIONS Our findings suggest negative effect of MBL deficiency (defined by genotype and phenotype) on progression of chronic hepatitis C in children and response to antiviral therapy.
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Brennan FH, Lee JD, Ruitenberg MJ, Woodruff TM. Therapeutic targeting of complement to modify disease course and improve outcomes in neurological conditions. Semin Immunol 2016; 28:292-308. [PMID: 27049459 DOI: 10.1016/j.smim.2016.03.015] [Citation(s) in RCA: 58] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/01/2016] [Revised: 03/17/2016] [Accepted: 03/18/2016] [Indexed: 12/14/2022]
Abstract
The recognition that complement proteins are abundantly present and can have pathological roles in neurological conditions offers broad scope for therapeutic intervention. Accordingly, an increasing number of experimental investigations have explored the potential of harnessing the unique activation pathways, proteases, receptors, complexes, and natural inhibitors of complement, to mitigate pathology in acute neurotrauma and chronic neurodegenerative diseases. Here, we review mechanisms of complement activation in the central nervous system (CNS), and explore the effects of complement inhibition in cerebral ischemic-reperfusion injury, traumatic brain injury, spinal cord injury, Alzheimer's disease, amyotrophic lateral sclerosis, Parkinson's disease and Huntington's disease. We consider the challenges and opportunities arising from these studies. As complement therapies approach clinical translation, we provide perspectives on how promising complement-targeted therapeutics could become part of novel and effective future treatment options to improve outcomes in the initiation and progression stages of these debilitating CNS disorders.
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Affiliation(s)
- Faith H Brennan
- School of Biomedical Sciences, The University of Queensland, Brisbane 4072, Australia
| | - John D Lee
- School of Biomedical Sciences, The University of Queensland, Brisbane 4072, Australia
| | - Marc J Ruitenberg
- School of Biomedical Sciences, The University of Queensland, Brisbane 4072, Australia; Queensland Brain Institute, The University of Queensland, Brisbane 4072, Australia; Trauma, Critical Care and Recovery, Brisbane Diamantina Health Partners, The University of Queensland, Brisbane 4072, Australia
| | - Trent M Woodruff
- School of Biomedical Sciences, The University of Queensland, Brisbane 4072, Australia.
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16
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MBL2 genotypes and their associations with MBL levels and NICU morbidity in a cohort of Greek neonates. J Immunol Res 2015; 2015:478412. [PMID: 25879044 PMCID: PMC4387979 DOI: 10.1155/2015/478412] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2014] [Revised: 02/23/2015] [Accepted: 02/28/2015] [Indexed: 12/16/2022] Open
Abstract
The objective of this study was to assess the frequency of MBL2 genotypes and their associations with MBL levels and various morbidities of a neonatal intensive care unit (NICU). One hundred and thirty-four (134) NICU (83 term and 51 preterm) and 150 healthy neonates were enrolled in the study. MBL2 genotype and MBL serum levels at birth were determined prospectively by PCR-RFLP-sequencing and enzyme-linked immunosorbent assay, respectively. NICU neonates displayed significantly lower MBL serum levels compared to healthy ones. MBL deficiency, defined as the low MBL2 expression group (XA/O and O/O), was significantly associated with an increased risk of respiratory morbidity, especially transient tachypnea of the newborn and respiratory distress syndrome (RDS). Moreover, an increase of 100 ng/mL of serum MBL levels decreases by 5% the risk of total respiratory morbidity and by 7% the risk of RDS, after correction for prematurity and sex and regardless of the presence of infections. Our study further supports the notion that neonates with MBL deficiency and low MBL serum levels at birth may be at higher risk of developing severe respiratory complications.
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17
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Beltrame MH, Catarino SJ, Goeldner I, Boldt ABW, de Messias-Reason IJ. The lectin pathway of complement and rheumatic heart disease. Front Pediatr 2014; 2:148. [PMID: 25654073 PMCID: PMC4300866 DOI: 10.3389/fped.2014.00148] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/28/2014] [Accepted: 12/29/2014] [Indexed: 12/19/2022] Open
Abstract
The innate immune system is the first line of host defense against infection and is comprised of humoral and cellular mechanisms that recognize potential pathogens within minutes or hours of entry. The effector components of innate immunity include epithelial barriers, phagocytes, and natural killer cells, as well as cytokines and the complement system. Complement plays an important role in the immediate response against microorganisms, including Streptococcus sp. The lectin pathway is one of three pathways by which the complement system can be activated. This pathway is initiated by the binding of mannose-binding lectin (MBL), collectin 11 (CL-K1), and ficolins (Ficolin-1, Ficolin-2, and Ficolin-3) to microbial surface oligosaccharides and acetylated residues, respectively. Upon binding to target molecules, MBL, CL-K1, and ficolins form complexes with MBL-associated serine proteases 1 and 2 (MASP-1 and MASP-2), which cleave C4 and C2 forming the C3 convertase (C4b2a). Subsequent activation of complement cascade leads to opsonization, phagocytosis, and lysis of target microorganisms through the formation of the membrane-attack complex. In addition, activation of complement may induce several inflammatory effects, such as expression of adhesion molecules, chemotaxis and activation of leukocytes, release of reactive oxygen species, and secretion of cytokines and chemokines. In this chapter, we review the general aspects of the structure, function, and genetic polymorphism of lectin-pathway components and discuss most recent understanding on the role of the lectin pathway in the predisposition and clinical progression of Rheumatic Fever.
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Affiliation(s)
- Marcia Holsbach Beltrame
- Department of Clinical Pathology, Hospital de Clínicas, Universidade Federal do Paraná , Curitiba , Brazil
| | - Sandra Jeremias Catarino
- Department of Clinical Pathology, Hospital de Clínicas, Universidade Federal do Paraná , Curitiba , Brazil
| | - Isabela Goeldner
- Department of Clinical Pathology, Hospital de Clínicas, Universidade Federal do Paraná , Curitiba , Brazil
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18
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Kjaer TR, Thiel S, Andersen GR. Toward a structure-based comprehension of the lectin pathway of complement. Mol Immunol 2013; 56:222-31. [DOI: 10.1016/j.molimm.2013.05.220] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2013] [Accepted: 05/09/2013] [Indexed: 01/19/2023]
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19
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Kjaer TR, Thiel S, Andersen GR. Toward a structure-based comprehension of the lectin pathway of complement. Mol Immunol 2013; 56:413-22. [DOI: 10.1016/j.molimm.2013.05.007] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2013] [Accepted: 05/14/2013] [Indexed: 01/19/2023]
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20
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Ikewaki N, Kulski JK, Inoko H. Regulation of CD93 Cell Surface Expression by Protein Kinase C Isoenzymes. Microbiol Immunol 2013; 50:93-103. [PMID: 16490927 DOI: 10.1111/j.1348-0421.2006.tb03774.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Human CD93, also known as complement protein 1, q subcomponent, receptor (C1qRp), is selectively expressed by cells with a myeloid lineage, endothelial cells, platelets, and microglia and was originally reported to be involved in the complement protein 1, q subcomponent (C1q)-mediated enhancement of phagocytosis. The intracellular molecular events responsible for the regulation of its expression on the cell surface, however, have not been determined. In this study, the effect of protein kinases in the regulation of CD93 expression on the cell surface of a human monocyte-like cell line (U937), a human NK-like cell line (KHYG-1), and a human umbilical vein endothelial cell line (HUV-EC-C) was investigated using four types of protein kinase inhibitors, the classical protein kinase C (cPKC) inhibitor Go6976, the novel PKC (nPKC) inhibitor Rottlerin, the protein kinase A (PKA) inhibitor H-89 and the protein tyrosine kinase (PTK) inhibitor herbimycin A at their optimum concentrations for 24 hr. CD93 expression was analyzed using flow cytometry and glutaraldehyde-fixed cellular enzyme-linked immunoassay (EIA) techniques utilizing a CD93 monoclonal antibody (mAb), mNI-11, that was originally established in our laboratory as a CD93 detection probe. The nPKC inhibitor Rottlerin strongly down-regulated CD93 expression on the U937 cells in a dose-dependent manner, whereas the other inhibitors had little or no effect. CD93 expression was down-regulated by Go6976, but not by Rottlerin, in the KHYG-1 cells and by both Rottlerin and Go6976 in the HUV-EC-C cells. The PKC stimulator, phorbol myristate acetate (PMA), strongly up-regulated CD93 expression on the cell surface of all three cell-lines and induced interleukin-8 (IL-8) production by the U937 cells and interferon-gamma (IFN-gamma) production by the KHYG-1 cells. In addition, both Go6976 and Rottlerin inhibited the up-regulation of CD93 expression induced by PMA and IL-8 or IFN-gamma production in the respective cell-lines. Whereas recombinant tumor necrosis factor-alpha (rTNF-alpha) slightly up-regulated CD93 expression on the U937 cells, recombinant interleukin-1beta (rIL-1beta), recombinant interleukin-2 (rIL-2), recombinant interferon-gamma (rIFN-gamma) and lipopolysaccharide (LPS) had no effect. Taken together, these findings indicate that the regulation of CD93 expression on these cells involves the PKC isoenzymes.
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Affiliation(s)
- Nobunao Ikewaki
- Institute of Immunology, Kyushu University of Health and Welfare, Nobeoka, Miyazaki, Japan
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21
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Boldt ABW, Goeldner I, de Messias-Reason IJT. Relevance of the lectin pathway of complement in rheumatic diseases. Adv Clin Chem 2012; 56:105-53. [PMID: 22397030 DOI: 10.1016/b978-0-12-394317-0.00012-1] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Due to its importance both in the clearance of pathogens that contribute as rheumatic etiological agents and in the disposal of apoptotic bodies and potential autoimmune initiators, deficiencies of the components of the lectin pathway of complement have been found to increase susceptibility and modulate the severity of most rheumatic disorders. This chapter introduces the general aspects of the structure, function, and genetics of lectin pathway components and summarizes current knowledge of the field regarding rheumatic diseases predisposition and modulation.
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Affiliation(s)
- Angelica B W Boldt
- Molecular Immunopathology Laboratory, Department of Medical Pathology, Federal University of Paraná, Curitiba, Brazil
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22
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Galvan MD, Foreman DB, Zeng E, Tan JC, Bohlson SS. Complement component C1q regulates macrophage expression of Mer tyrosine kinase to promote clearance of apoptotic cells. THE JOURNAL OF IMMUNOLOGY 2012; 188:3716-23. [PMID: 22422887 DOI: 10.4049/jimmunol.1102920] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Failure to efficiently clear apoptotic cells is linked to defects in development and the onset of autoimmunity. Complement component C1q is required for efficient engulfment of apoptotic cells in mice and humans; however, the molecular mechanisms leading to C1q-dependent engulfment are not fully understood. In this study, we used primary mouse macrophages to identify and characterize a novel molecular mechanism for macrophage-mediated C1q-dependent engulfment of apoptotic cells. We found that macrophage activation with C1q resulted in cycloheximide-sensitive enhanced engulfment, indicating a requirement for de novo protein synthesis. To investigate the cycloheximide-sensitive pathway, C1q-elicited macrophage transcripts were identified by microarray. C1q triggered the expression of Mer tyrosine kinase (Mer) and the Mer ligand growth arrest-specific 6: a receptor-ligand pair that mediates clearance of apoptotic cells. Full-length native C1q, and not the collagen-like tail or heat-denatured protein, stimulated Mer expression. This novel pathway is specific to C1q because mannose-binding lectin, a related collectin, failed to upregulate Mer expression and function. Soluble Mer-Fc fusion protein inhibited C1q-dependent engulfment of apoptotic cells, indicating a requirement for Mer. Moreover, Mer-deficient macrophages failed to respond to C1q with enhanced engulfment. Our results suggest that C1q elicits a macrophage phenotype specifically tailored for apoptotic cell clearance, and these data are consistent with the established requirement for C1q in prevention of autoimmunity.
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Affiliation(s)
- Manuel D Galvan
- Department of Biological Sciences, Eck Institute for Global Health, University of Notre Dame, Notre Dame, IN 46556, USA
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24
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Abstract
PPARs, most notably PPAR-gamma, play a crucial role in regulating the activation of alveolar macrophages, which in turn occupy a pivotal place in the immune response to pathogens and particulates drawn in with inspired air. In this review, we describe the dual role of the alveolar macrophage as both a first-line defender through its phagocytotic activity and a regulator of the immune response. Depending on its state of activation, the alveolar macrophage may either enhance or suppress different aspects of immune function in the lung. We then review the role of PPAR-gamma and its ligands in deactivating alveolar macrophages-thus limiting the inflammatory response that, if unchecked, could threaten the essential respiratory function of the alveolus-while upregulating the cell's phagocytotic activity. Finally, we examine the role that inadequate or inappropriate PPAR-gamma responses play in specific lung diseases.
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25
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Recombinant form of human wild type mannan-binding lectin (MBL/A) but not its structural variant (MBL/C) promotes phagocytosis of zymosan by activating complement. Mol Immunol 2010; 47:2505-14. [PMID: 20579738 DOI: 10.1016/j.molimm.2010.05.292] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2010] [Accepted: 05/27/2010] [Indexed: 01/22/2023]
Abstract
Mannan-binding lectin (MBL) mediates innate immune responses, such as activation of the complement lectin pathway and phagocytosis, to help fight infections. In the present study, employing recombinant forms of human MBL (rMBL), the role of wild type MBL (rMBL/A) and its structural variant rMBL/C in mediating THP-1 phagocytosis of fluorescent-labeled zymosan was examined and compared to MBL purified from human plasma (pMBL/A). Flow cytometric analyses revealed that opsonization of zymosan with rMBL/A and pMBL/A (0.5-30microg/ml) resulted in a 1.9- and 2.7-fold enhancement in its uptake by THP-1 cells in the presence of serum that was depleted of both MBL and the classical pathway component, C1q (MBL/C1q Dpl serum). In contrast, no enhancement in phagocytosis was observed when zymosan was opsonized with rMBL/C. Addition of MBL monoclonal antibody, EDTA, or mannan to the opsonization reaction mixture inhibited THP-1 phagocytosis of pMBL/A opsonized zymosan. Heat inactivation of MBL/C1q Dpl serum abolished the 2-fold increase in phagocytosis and in the absence of serum the direct opsonic activity of MBL did not contribute significantly to the uptake of zymosan into THP-1 cells. Activation products of complement components C3 and C4 were deposited on zymosan opsonized with pMBL/A and rMBL/A but not rMBL/C indicating that MBL-mediated phagocytosis of zymosan requires activation of the complement lectin pathway. The findings imply that impaired MBL-mediated phagocytosis may put individuals homozygous for the mutant allele MBL/C but not wild type MBL/A at increased risk to infections such as yeast.
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26
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Ikewaki N, Yamao H, Kulski JK, Inoko H. Flow cytometric identification of CD93 expression on naive T lymphocytes (CD4(+)CD45RA (+) cells) in human neonatal umbilical cord blood. J Clin Immunol 2010; 30:723-33. [PMID: 20512406 DOI: 10.1007/s10875-010-9426-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2009] [Accepted: 05/12/2010] [Indexed: 11/24/2022]
Abstract
Human CD93 has a molecular weight of about 100 kDa and is selectively expressed by myeloid cell lineages in peripheral blood (PB) mononuclear cells. Although CD93 was initially identified as a receptor for complement component 1, subcomponent q phagocytosis (C1qRp) involved in the C1q-mediated enhancement of the phagocytosis of various antigens, several recent studies have reported that CD93 is not a receptor for the C1q-mediated enhancement of phagocytosis. The expression patterns of CD93 have been previously investigated in PB mononuclear cells (lymphocytes, monocytes, and granulocytes) from adult PB and neonatal umbilical cord blood (UCB), and the expression of CD93 was not found on lymphocytes from either normal adult PB or neonatal UCB. However, the detection of CD93 expression in neonatal UCB using CD93 monoclonal antibodies (mAbs) that recognize different antigenic epitopes remains poorly understood. In this study, we examined the expression of CD93 on lymphocytes, monocytes, and granulocytes from neonatal UCB using four different types of CD93 mAb detection probes, mNI-11, R139, R3, and X-2, using flow cytometric and western blot analyses. We found that CD93, as defined using all four mAbs, was expressed on monocytes and granulocytes in PB mononuclear cells from adult PB and neonatal UCB. On the other hand, we observed for the first time that the expression of CD93 on lymphocytes in neonatal UCB can only be detected using the mNI-11 mAb, established in our laboratory, and not with commercially available CD93 mAbs (R139, R3, and X-2). However, CD93 expression on lymphocytes from normal adults was not detected using any of the four CD93 mAbs. Two-color flow cytometric analyses showed that the CD93 recognized by mNI-11 mAb was expressed on CD3(+) T lymphocytes (mainly CD4(+) helper T lymphocytes), but not on CD19(+) B lymphocytes or on CD8(+) suppressor/cytotoxic T lymphocytes from neonatal UCB. In addition, CD93 was expressed on CD45RA(+) (naive antigen) lymphocytes from neonatal UCB, but not on CD45RO(+) (memory antigen) lymphocytes from neonatal UCB or on CD45RA(+) and CD45RO(+) lymphocytes from normal adult PB. Three-color flow cytometric analysis showed that CD93 was co-expressed on naive T lymphocytes (CD4(+)CD45RA(+)) from neonatal UCB. In a western blot analysis, the CD93 mAb (mNI-11) immunoprecipitated at a molecular weight of 98 kDa, identified as a CD93 molecule, in the CD4(+)CD45RA(+) cells from neonatal UCB but not from adult PB, similar to the results in the human monocyte-like cell line U937 (human CD93-positive cells). Taken together, these results provide the first direct evidence of a novel/naive cell population (CD4(+)CD45RA(+)CD93(+)) in neonatal UCB that may have an important role in cell biology, transplantation, and immature/mature immune responses.
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Affiliation(s)
- Nobunao Ikewaki
- Department of Animal Pharmaceutical Science, Kyushu University of Health and Welfare School of Pharmaceutical Sciences, 1714-1 Yoshino-cho, Nobeoka, Miyazaki 882-8508, Japan.
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27
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Abstract
Innate immunity is the earliest response to invading microbes and acts to contain infection in the first minutes to hours of challenge. Unlike adaptive immunity that relies upon clonal expansion of cells that emerge days after antigenic challenge, the innate immune response is immediate. Soluble mediators, including complement components and the mannose binding lectin (MBL) make an important contribution to innate immune protection and work along with epithelial barriers, cellular defenses such as phagocytosis, and pattern-recognition receptors that trigger pro-inflammatory signaling cascades. These four aspects of the innate immune system act in concert to protect from pathogen invasion. Our work has focused on understanding the protection provided by this complex defense system and, as discussed in this review, the particular contribution of soluble mediators such as MBL and phagocytic cells. Over the past two decades both human epidemiological data and mouse models have indicated that MBL plays a critical role in innate immune protection against a number of pathogens. As demonstrated by our recent in vitro work, we show that MBL and the innate immune signaling triggered by the canonical pattern-recognition receptors (PRRs), the Toll-like receptors (TLRs), are linked by their spatial localization to the phagosome. These observations demonstrated a novel role for MBL as a TLR co-receptor and establishes a new paradigm for the role of opsonins, which we propose to function not only to increase microbial uptake but also to spatially coordinate, amplify, and synchronize innate immune defenses mechanism. In this review we discuss both the attributes of MBL that make it a unique soluble pattern recognition molecule and also highlight its broader role in coordinating innate immune activation.
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Affiliation(s)
- W K Eddie Ip
- Department of Immunobiology, Yale University School of Medicine, New Haven, CT, USA
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28
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Eisen DP. Mannose-binding lectin deficiency and respiratory tract infection. J Innate Immun 2009; 2:114-22. [PMID: 20375630 PMCID: PMC7179718 DOI: 10.1159/000228159] [Citation(s) in RCA: 94] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2008] [Accepted: 12/03/2008] [Indexed: 11/19/2022] Open
Abstract
Mannose-binding lectin (MBL) is an innate immune system pattern recognition protein that kills a wide range of pathogenic microbes through complement activation. A substantial proportion of all human populations studied to date have MBL deficiency due to MBL2 polymorphisms, which potentially increases susceptibility to infectious disease. MBL binds numerous respiratory pathogens but the capsule of Streptococcus pneumoniae abrogates its efficient binding. Clinical studies in humans have shown that MBL deficiency appears to predispose to severe respiratory tract infection. A recent meta-analysis shows that MBL deficiency was associated with death in patients with pneumococcal infection after adjusting for bacteraemia and comorbidities. Human clinical studies have also shown associations between MBL deficiency and various less common respiratory infections. Intracellular infections like tuberculosis may be less common with MBL deficiency because of reduced opsonophagocytosis. Lung secretions contain small amounts of MBL that are potentially sufficient to activate complement, but their measurement is confounded by dilution inherent in collection techniques. Therefore, if this protein does play a role in pulmonary immunity it is presumably through prevention of haematogenous dissemination of respiratory pathogens while adding to mucosal defences. Ficolins are collectins that are structurally and functionally related to MBL and are either present in serum or expressed in tissues including the lung. Limited variation in serum levels of L- and H-ficolin result from the presence of FCN2 and FCN3 polymorphisms. Initial studies on the impact of FCN2 polymorphisms or low L-ficolin levels do not seem to show major associations with respiratory infection. MBL is being developed as a new immunotherapeutic agent for prevention of infection in immunocompromised hosts. The available literature suggests that it may also be of benefit in MBL deficient patients with severe pneumonia. This review concentrates on clinical associations between MBL deficiency and susceptibility to respiratory tract infection.
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Affiliation(s)
- Damon P Eisen
- Victorian Infectious Diseases Service, Royal Melbourne Hospital, Parkville, Vic., Australia.
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Haczku A. Protective role of the lung collectins surfactant protein A and surfactant protein D in airway inflammation. J Allergy Clin Immunol 2008; 122:861-79; quiz 880-1. [PMID: 19000577 DOI: 10.1016/j.jaci.2008.10.014] [Citation(s) in RCA: 91] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2008] [Revised: 10/13/2008] [Accepted: 10/13/2008] [Indexed: 12/30/2022]
Abstract
The acute inflammatory airway response is characterized by a time-dependent onset followed by active resolution. Emerging evidence suggests that epithelial cells of the proximal and distal air spaces release host defense mediators that can facilitate both the initiation and the resolution part of inflammatory airway changes. These molecules, also known as the hydrophilic surfactant proteins (surfactant protein [SP]-A and SP-D) belong to the class of collagenous lectins (collectins). The collectins are a small family of soluble pattern recognition receptors containing collagenous regions and C-type lectin domains. SP-A and SP-D are most abundant in the lung. Because of their structural uniqueness, specific localization, and functional versatility, lung collectins are important players of the pulmonary immune responses. Recent studies in our laboratory and others indicated significant associations of lung collectin levels with acute and chronic airway inflammation in both animal models and patients, suggesting the usefulness of these molecules as disease biomarkers. Research on wild-type and mutant recombinant molecules in vivo and in vitro showed that SP-A and SP-D bind carbohydrates, lipids, and nucleic acids with a broad-spectrum specificity and initiate phagocytosis of inhaled pathogens as well as apoptotic cells. Investigations on gene-deficient and conditional overexpresser mice indicated that lung collectins also directly modulate innate immune cell function and T-cell-dependent inflammatory events. Thus, these molecules have a unique, dual-function capacity to induce pathogen elimination and control proinflammatory mechanisms, suggesting a potential suitability for therapeutic prevention and treatment of chronic airway inflammation. This article reviews evidence supporting that the lung collectins play an immune-protective role and are essential for maintenance of the immunologic homeostasis in the lung.
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Affiliation(s)
- Angela Haczku
- Department of Medicine, University of Pennsylvania, Philadelphia, PA, USA.
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30
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Csencsits K, Burrell BE, Lu G, Eichwald EJ, Stahl GL, Bishop DK. The classical complement pathway in transplantation: unanticipated protective effects of C1q and role in inductive antibody therapy. Am J Transplant 2008; 8:1622-30. [PMID: 18557731 PMCID: PMC2587427 DOI: 10.1111/j.1600-6143.2008.02295.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Though complement (C) deposition within the transplant is associated with allograft rejection, the pathways employed have not been established. In addition, evidence suggests that C-mediated cytolysis may be necessary for the tolerance-inducing activities of mAb therapies. Hence, we assessed the role of the classical C pathway in acute allograft rejection and its requirement for experimental mAb therapies. C1q-deficient (C1q-/-) recipients rejected allografts at a faster rate than wild-type (WT) recipients. This rejection was associated with exacerbated graft pathology but not with enhanced T-cell responses in C1q-/- recipients. However, the humoral response to donor alloantigens was accelerated in C1q-/- mice, as an early IgG response and IgG deposition within the graft were observed. Furthermore, deposition of C3d, but not C4d was observed in grafts isolated from C1q-/- recipients. To assess the role of the classical C pathway in inductive mAb therapies, C1q-/- recipients were treated with anti-CD4 or anti-CD40L mAb. The protective effects of anti-CD4 mAb were reduced in C1q-/- recipients, however, this effect did not correlate with ineffective depletion of CD4+ cells. In contrast, the protective effects of anti-CD40L mAb were less compromised in C1q-/- recipients. Hence, this study reveals unanticipated roles for C1q in the rejection process.
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Affiliation(s)
- K. Csencsits
- Section of General Surgery, Department of Surgery, University of Michigan School of Medicine, Ann Arbor, MI 48109,*Corresponding Author: Keri Csencsits, Ph.D., Department of Pathology and Laboratory Medicine, 2.250 MSB, 6431 Fannin, University of Texas Health Science Center at Houston, Houston, TX 77030, Phone: 713-500-7235//Fax: 713-500-0574,
| | - B. E. Burrell
- Graduate Program in Immunology, University of Michigan School of Medicine, Ann Arbor, MI 48109
| | - G. Lu
- Section of General Surgery, Department of Surgery, University of Michigan School of Medicine, Ann Arbor, MI 48109
| | - E. J. Eichwald
- Department of Pathology, University of Utah School of Medicine, Salt Lake City, UT 84132
| | - G. L. Stahl
- Center for Experimental Therapeutics and Reperfusion Injury, Department of Anesthesiology, Perioperative and Pain Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA 02115
| | - D. K. Bishop
- Section of General Surgery, Department of Surgery, University of Michigan School of Medicine, Ann Arbor, MI 48109, Graduate Program in Immunology, University of Michigan School of Medicine, Ann Arbor, MI 48109
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Dzwonek AB, Neth OW, Thiébaut R, Gulczynska E, Chilton M, Hellwig T, Bajaj-Elliott M, Hawdon J, Klein NJ. The role of mannose-binding lectin in susceptibility to infection in preterm neonates. Pediatr Res 2008; 63:680-5. [PMID: 18317236 DOI: 10.1203/pdr.0b013e31816fdbff] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Preterm neonates are susceptible to infection due to a combination of sub-optimal immunity and increased exposure to invasive organisms. Mannose-binding lectin (MBL) is a component of the innate immune system, which may be especially important in the neonatal setting. The objective of this study was to investigate the impact of MBL on susceptibility and severity of infection in preterm neonates during their first month of life. One hundred fifty eight preterm neonates were genotyped for MBL mutations by heteroduplex analyses. Consecutive serum MBL levels were measured by ELISA and clinical and laboratory data, including blood cultures, were collected for each baby. A third of the premature neonates had genetically determined MBL deficiency. In addition, MBL levels were also low in the first week of life and lower in neonates with a wild type genotype who were less than 28 wk gestation or a birth weight of less than 1000 g, thereby increasing the number of neonates with a low MBL level at birth. MBL deficiency was associated with an increased risk of sepsis (p < 0.01). This study indicates that MBL levels are low in neonates at birth and renders premature neonates to an increased risk of infection.
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Affiliation(s)
- Agnieszka B Dzwonek
- Department of Infectious Diseases and Microbiology, University College London, WC1N 3JN, United Kingdom
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Abstract
Data from several investigators suggest that the alpha2beta1 integrin, a receptor for collagens, laminins, decorin, E-cadherin, matrix metalloproteinase-1, endorepellin, and several viruses, is required for innate immunity and regulation of autoimmune/allergic disorders. We demonstrated that the innate immune response to Listeria monocytogenes required alpha2beta1 integrin expression by peritoneal mast cells (PMCs). Ligation of the alpha2beta1 integrin by C1q contained in immune complexes comprised of Listeria and antibody was required for PMC activation in vitro and in vivo. However, ligation of the alpha2beta1 integrin alone was insufficient to activate cytokine secretion, suggesting that one or more additional signals emanating from a coreceptor were required for PMC activation. Here, we demonstrate that C1q, but neither other complement proteins nor FcRgamma, is required for early innate immune response to Listeria. The binding of Listeria's Internalin B (InlB) to hepatocyte growth factor receptor (HGF-R)/c-met provides the costimulatory function required for PMC activation. Either HGF or Listeria InlB bound to c-met and either C1q or type I collagen bound to alpha2beta1 integrin stimulates PMC activation. These findings suggest that crosstalk between c-met and the alpha2beta1 integrin may contribute to mast-cell activation in autoimmune and inflammatory disorders.
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Young KM, Russell S, Smith M, Huber P, Ostland VE, Brooks AS, Anthony Hayes M, Lumsden JS. Bacterial-binding activity and plasma concentration of ladderlectin in rainbow trout (Oncorhynchus mykiss). FISH & SHELLFISH IMMUNOLOGY 2007; 23:305-15. [PMID: 17383895 DOI: 10.1016/j.fsi.2006.10.014] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/12/2006] [Revised: 10/16/2006] [Accepted: 10/30/2006] [Indexed: 05/14/2023]
Abstract
Soluble, defense lectins bind conserved microbial patterns leading to pathogen opsonization, enhanced phagocytosis and activation of complement. These immune functions, however, vary widely among individuals due to genetic and acquired differences affecting binding capacity or plasma concentration. Most evidence for the defensive function of soluble lectins is based on mammals, but several functionally homologous, but less well-characterized, lectins have been identified in fish. In this study, we compared binding of rainbow trout plasma ladderlectin to relevant, intact bacterial targets. A polyclonal antiserum raised against a synthetic peptide identical to the 20 N-terminal amino acids of the reduced 16 kDa rainbow trout ladderlectin subunit was used to detect plasma ladderlectin in immunoblots and indirect enzyme-linked immunosorbent assay (ELISA). Ladderlectin binding to Aeromonas salmonicida subsp. salmonicida, Aeromonas hydrophila, Yersinia ruckeri and Pseudomonas sp. was detected by PAGE and immunoblots of saccharide elutions from intact bacteria incubated in the presence of normal trout plasma. Although plasma concentrations of immunoreactive ladderlectin were low in the majority of trout, significant (P < 0.0001) variation between individual fish was observed in two separate populations. In addition, one population demonstrated a subset of individuals whose ladderlectin levels were approximately seven-fold higher than the population median. These findings indicate that rainbow trout have variable amounts of plasma ladderlectin capable of binding to the surfaces of several relevant bacterial targets.
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Affiliation(s)
- Karrie M Young
- Fish Pathology Laboratory, Ontario Veterinary College, University of Guelph, Guelph, Ontario, Canada, N1G 2W1
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Takahashi K, Ezekowitz RAB. The role of the mannose-binding lectin in innate immunity. Clin Infect Dis 2007; 41 Suppl 7:S440-4. [PMID: 16237644 DOI: 10.1086/431987] [Citation(s) in RCA: 90] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
The innate immune system, which includes mannose-binding lectin (MBL), recognizes a broad range of molecular patterns on a broad range of infectious agents and is able to distinguish them from self. MBL is a liver-derived serum protein and is secreted into the serum, where it can activate an immune response before the induction of antigen-specific immunity. Circumstantial evidence in human populations suggests that low serum levels of MBL predispose to infection. To analyze the role of MBL in vivo, we created MBL-null mice and challenged these mice with infection under various conditions. Our results suggest that MBL plays an important role as a first-line host defense against certain infectious agents. In addition, it is likely that MBL is a key regulator of inflammation beyond expected roles in the infection.
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Affiliation(s)
- Kazue Takahashi
- Department of Pediatrics, Harvard Medical School, Massachusetts General Hospital, Boston, MA 02114, USA.
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Kaur S, Gupta VK, Thiel S, Sarma PU, Madan T. Protective role of mannan-binding lectin in a murine model of invasive pulmonary aspergillosis. Clin Exp Immunol 2007; 148:382-9. [PMID: 17335555 PMCID: PMC1868875 DOI: 10.1111/j.1365-2249.2007.03351.x] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Innate immune molecules such as lung collectins and serum pentraxins have evolved as important host defence proteins against Aspergillus fumigatus, a medically important opportunistic fungal pathogen. Mannan-binding lectin (MBL), an opsonin and lectin complement pathway activator, constitutes another vital player of innate immunity against several pathogenic organisms in the serum. Studies have reported significant binding of MBL to A. fumigatus; however, the protective role of MBL against A. fumigatus-mediated invasive disease remains elusive. Henceforth, we investigated the contribution of externally administered recombinant human (rh) MBL towards anti-fungal defence in invasive pulmonary aspergillosis (IPA) by in vivo and in vitro studies. In murine models of IPA with corticosteroid-induced immunosuppression, rhMBL-treated mice showed 80% survival compared to untreated IPA mice with no survivors. Treated IPA mice also showed a marked increase in tumour necrosis factor (TNF)-alpha and interleukin (IL)-1alpha and a significant decrease in pulmonary fungal hyphae and IL-10. In vitro, rhMBL-bound A. fumigatus conidia showed a dose-dependent increase in the deposition of C4b, the first product of the lectin pathway. There was an enhanced uptake of A. fumigatus conidia by the polymorphonuclear cells (PMNs) in the presence of rhMBL that increased further in the presence of MBL supplemented with MBL-deficient serum. However, an increase in the oxidative burst of PMNs and A. fumigatus killing were observed only when MBL was supplemented with MBL-deficient serum. The study suggests a therapeutic role of ex vivo-administered MBL in host defence against aspergillosis, possibly through MBL-mediated complement activation and other protective mechanisms aimed both directly at the pathogen, and indirectly through modulation of the host inflammatory responses.
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Affiliation(s)
- S Kaur
- Molecular Biochemistry and Diagnostics, Institute of Genomics and Integrative Biology, Mall Road, Delhi, India
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36
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Manco M, Fernandez-Real JM, Equitani F, Vendrell J, Valera Mora ME, Nanni G, Tondolo V, Calvani M, Ricart W, Castagneto M, Mingrone G. Effect of massive weight loss on inflammatory adipocytokines and the innate immune system in morbidly obese women. J Clin Endocrinol Metab 2007; 92:483-90. [PMID: 17105839 DOI: 10.1210/jc.2006-0960] [Citation(s) in RCA: 118] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/09/2023]
Abstract
CONTEXT Obesity may be regarded as a low-grade inflammatory state. OBJECTIVE The aim of this study was to evaluate changes in pro-inflammatory adipocytokines and the innate immune system, cardiovascular risk, and insulin sensitivity after massive weight loss. DESIGN This was a longitudinal study. SETTING The study was conducted at Catholic University, Rome. SUBJECTS AND METHODS There were 10 normoglucose-tolerant obese women evaluated before and 36 months after bilio-pancreatic diversion (BPD). Glucose sensitivity (M value) was estimated using the euglycemic-hyperinsulinemic clamp. Mannan-binding lectin (MBL), bactericidal/permeability increasing protein (BPI), alpha-defensins, soluble CD14 receptor (sCD14), C-reactive protein, adiponectin, leptin, visfatin, IL-6, and TNF-alpha were assayed. RESULTS After massive weight loss (53% of excess body weight), leptin (P <or= 0.0001), IL-6 (P <or= 0.0001), alpha-defensins (P <or= 0.001), and C-reactive protein (P <or= 0.0001) decreased significantly. Adiponectin increased significantly (P <or= 0.001). Of the nine subjects who lost more than 20% of body mass index, sCD14 (2.87 +/- 0.5 to 2.55 +/- 0.5; P = 0.016) and visfatin levels (12.20 +/- 0.93 to 10.63 +/- 1.93 ng/ml; P = 0.045) decreased significantly. No significant changes were observed in TNF-alpha, BPI, or MBL. Insulin sensitivity more than doubled after BPD (P <or= 0.0001). sCD14 changes were significantly associated with body mass index (r0 = 0.80; P = 0.003) and M changes (r0 = -0.59; P = 0.03). MBL correlated with insulin sensitivity in obese (r0 = 0.93; P = 0.0001) and post-BPD women (r(0) = 0.66; P = 0.038). Adiponectin correlated negatively with cardiovascular risk (r0 = -0.709; P = 0.02) and IL-6 (r0 = -0.634; P = 0.05). Multiple linear regression analysis showed that changes in sCD14 were also significantly related to changes in insulin sensitivity. CONCLUSIONS Surgically induced weight loss is capable of reversing low-grade inflammation, at least partially. The relationships between sCD14, MBL, BPI, and glucose sensitivity, and the role of TNF-alpha in obesity warrant further investigation.
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Affiliation(s)
- Melania Manco
- Department of Internal Medicine, Catholic University, Rome, Italy.
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Xiang SD, Scholzen A, Minigo G, David C, Apostolopoulos V, Mottram PL, Plebanski M. Pathogen recognition and development of particulate vaccines: does size matter? Methods 2007; 40:1-9. [PMID: 16997708 DOI: 10.1016/j.ymeth.2006.05.016] [Citation(s) in RCA: 436] [Impact Index Per Article: 25.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2006] [Accepted: 05/05/2006] [Indexed: 01/08/2023] Open
Abstract
The use of particulate carriers holds great promise for the development of effective and affordable recombinant vaccines. Rational development requires a detailed understanding of particle up-take and processing mechanisms to target cellular pathways capable of stimulating the required immune responses safely. These mechanisms are in turn based on how the host has evolved to recognize and process pathogens. Pathogens, as well as particulate vaccines, come in a wide range of sizes and biochemical compositions. Some of these also provide 'danger signals' so that antigen 'senting cells (APC), usually dendritic cells (DC), acquire specific stimulatory activity. Herein, we provide an overview of the types of particles currently under investigation for the formulation of vaccines, discuss cellular uptake mechanisms (endocytosis, macropinocytosis, phagocytosis, clathrin-dependent and/or caveloae-mediated) for pathogens and particles of different sizes, as well as antigen possessing and presentation by APC in general, and DC in particular. Since particle size and composition can influence the immune response, inducing humoral and/or cellular immunity, activating CD8 T cells and/or CD4 T cells of T helper 1 and/or T helper 2 type, particle characteristics have a major impact on vaccine efficacy. Recently developed methods for the formulation of particulate vaccines are presented in this issue of Methods, showcasing a range of "cutting edge" particulate vaccines that employ particles ranging from nano to micro-sized. This special issue of Methods further addresses practical issues of production, affordability, reproducibility and stability of formulation, and also includes a discussion of the economic and regulatory challenges encountered in developing vaccines for veterinary use and for common Third World infectious diseases.
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Affiliation(s)
- Sue D Xiang
- Vaccine and Infectious Diseases Laboratory, Burnet Institute at Austin, Studley Road, Heidelberg, Vic. 3084, Australia
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Zutter MM, Edelson BT. The alpha2beta1 integrin: a novel collectin/C1q receptor. Immunobiology 2007; 212:343-53. [PMID: 17544819 DOI: 10.1016/j.imbio.2006.11.013] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2006] [Accepted: 11/27/2006] [Indexed: 11/18/2022]
Abstract
Our laboratory focuses on the alpha2beta1 integrin, a receptor for a number of matrix and non-matrix ligands, including collagens, laminins, decorin, E-cadherin, matrix metalloproteinase-1 (MMP-1), endorepellin, and several viruses. The alpha2beta1 integrin is expressed on numerous different cell types, including epithelial cells, endothelial cells, fibroblasts, and hematopoietic elements, including platelets and specific subsets of leukocytes. Although alpha2beta1 integrin expression is widespread, it is not ubiquitous. Rather, it is expressed in a differentiation-dependent and activation-dependent manner. Interactions between the alpha2beta1 integrin and extracellular matrix ligands have been implicated in important biological processes including inflammation and immunity. Studies from a number of laboratories have demonstrated a role for the alpha2beta1 integrin during the immune response. Our laboratory generated an alpha2beta1 integrin-deficient mouse to define the role of the alpha2beta1 integrin in vivo. Our studies demonstrated that the alpha2-null mice have a profound defect in the innate immune response. We have recently reported the identification of a novel family of ligands for the alpha2beta1 integrin, which include C1q and the collectins. The goal of this article is to review the important role that the interaction between the alpha2beta1 integrin and C1q plays in the innate immune response. The identification of C1q and the collectins as ligands for the alpha2beta1 integrin suggests that the integrin may play important roles in a number of immunological responses.
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Affiliation(s)
- Mary M Zutter
- Department of Pathology, Cancer Biology and Immunology, Vanderbilt University School of Medicine, C3321A MCN, 1161 21st Avenue S, Nashville, TN 37232, USA.
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Abstract
The human collectin, mannose‐binding lectin (MBL), is an important protein of the humoral innate immune system. With multiple carbohydrate‐recognition domains, it is able to bind to sugar groups displayed on the surfaces of a wide range of microorganisms and thereby provide first‐line defence. Importantly, it also activates the complement system through a distinctive third pathway, independent of both antibody and the C1 complex. Three single point mutations in exon 1 of the expressed human MBL‐2 gene appear to impair the generation of functional oligomers. Such deficiencies of functional protein are common in certain populations, e.g. in sub‐Saharan Africa, but virtually absent in others, e.g. indigenous Australians. MBL disease association studies have been a fruitful area of research and implicate a role for MBL in infective, inflammatory and autoimmune disease processes. Overall, there appears to be a genetic balance in which individuals generally benefit from high levels of the protein. However, in certain situations, reduced levels of circulating MBL may be beneficial to the host and this may explain the persistence of the deleterious gene polymorphisms in many population groups.
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Affiliation(s)
- R M Dommett
- Infectious Diseases and Microbiology Unit, Institute of Child Health, UCL, 30 Guilford Street, London WC1N 1EH, UK
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40
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Fernández-Real JM, Straczkowski M, Vendrell J, Soriguer F, Pérez Del Pulgar S, Gallart L, López-Bermejo A, Kowalska I, Manco M, Cardona F, García-Gil MM, Mingrone G, Richart C, Ricart W, Zorzano A. Protection from inflammatory disease in insulin resistance: the role of mannan-binding lectin. Diabetologia 2006; 49:2402-11. [PMID: 16955210 DOI: 10.1007/s00125-006-0381-6] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/13/2006] [Accepted: 05/30/2006] [Indexed: 12/27/2022]
Abstract
AIMS/HYPOTHESIS Decreased sensing of the innate immune system may lead to chronic activation of the inflammatory cascade. We hypothesised that mannan-binding lectin (MBL) deficiency may confer risk of obesity and insulin resistance. MATERIALS AND METHODS We performed a cross-sectional study of MBL protein concentration (n=434) and MBL2 gene mutations (exon 1) (n=759) in association with obesity, markers of inflammation and insulin action (euglycaemic clamp, n=113), and a longitudinal study of MBL protein before and after weight loss in obese patients (n=10). We also studied the effects of MBL in vitro in muscle cells and circulating MBL-A (mouse equivalent of human MBL) in a mouse model. RESULTS Among 434 consecutive non-diabetic men, the age-adjusted serum MBL concentration was lower in obese subjects than in lean subjects (median: 959 microg/ml [interquartile range: 116.8-2,044 microg/ml] vs 1,365 [467-2,513] microg/ml; p=0.01) and was accompanied by increased serum inflammatory markers. Insulin action correlated significantly with serum MBL (r=0.49, p<0.0001). Serum MBL concentration increased by a median of 110.2% after weight loss. The change in serum concentration of MBL was positively associated with the increase in insulin sensitivity (r=0.713, p=0.021). At least one MBL2 gene mutation was present in 48.2% of obese vs 39.3% of non-obese subjects (p=0.037). The plasma concentration of MBL-A was lower in insulin-resistant obese ob/ob mice, as was the glucose/insulin ratio. Incubation of rat soleus muscle with human MBL markedly increased fatty acid oxidation. CONCLUSIONS/INTERPRETATION These findings suggest that MBL, previously thought only to be involved in inflammation and immune system function, affects metabolic pathways.
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Affiliation(s)
- J M Fernández-Real
- Section of Diabetes, Endocrinology and Nutrition, University Hospital of Girona 'Dr Josep Trueta', Carretera de França s/n, 17007, Girona, Spain.
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Bohlson SS, Fraser DA, Tenner AJ. Complement proteins C1q and MBL are pattern recognition molecules that signal immediate and long-term protective immune functions. Mol Immunol 2006; 44:33-43. [PMID: 16908067 DOI: 10.1016/j.molimm.2006.06.021] [Citation(s) in RCA: 141] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2006] [Revised: 06/21/2006] [Accepted: 06/26/2006] [Indexed: 12/16/2022]
Abstract
C1q and mannose binding lectin, members of the "defense collagen" family, are pattern recognition molecules that can trigger rapid enhanced phagocytosis resulting in efficient containment of pathogens or clearance of cellular debris, apoptotic cells and immune complexes. In addition, interaction of C1q and mannose binding lectin with the phagocyte alters subsequent phagocyte cytokine synthesis, and thus may have important implications in directing acute inflammation as well as long-term protective immunity. The importance of the role of defense collagens in phagocytosis of apoptotic cells is highlighted by studies in vivo of mice deficient in C1q, pulmonary surfactant D and mannose binding lectin in which there is delayed clearance of apoptotic cells. Indeed, deficiency of C1q is a risk factor for the development of autoimmunity in both humans and mice, consistent with the hypothesis that inefficient clearance of apoptotic cells results in release of autoantigens and contributes to the pathology associated with autoimmune diseases such as systemic lupus erythematosus. Further understanding of the importance of C1q and mannose binding lectin in the clearance of apoptotic cells and regulation of cytokine synthesis and identification of the receptors implicated in mediating these processes should provide novel targets for therapeutic intervention in the control and manipulation of the immune response in terms of both host defense against infectious disease and tissue repair and remodeling.
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Affiliation(s)
- Suzanne S Bohlson
- Department of Molecular Biology and Biochemistry, Center for Immunology, University of California, Irvine, CA 92697, USA
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42
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Haczku A. Role and regulation of lung collectins in allergic airway sensitization. Pharmacol Ther 2005; 110:14-34. [PMID: 16226313 DOI: 10.1016/j.pharmthera.2005.08.008] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2005] [Accepted: 08/23/2005] [Indexed: 12/21/2022]
Abstract
Inhalation of allergens in atopic patients results in a characteristic inflammatory response while in normal, healthy individuals it elicits no symptoms. The mechanisms by which the pulmonary immune system accomplishes elimination of inhaled particles and suppression of the ensuing inflammatory response are poorly understood. Based on their structural uniqueness, specific localization and functional versatility the hydrophilic surfactant proteins [surfactant protein (SP)-A and SP-D] are important candidate regulators of these processes. Recent studies in our laboratory and others indicated significant changes in levels of these molecules during the asthmatic response in animal models as well as in asthmatic patients. Because of their capability to directly inhibit T-cell activation and T-cell-dependent allergic inflammatory events, SP-A and SP-D may be significant contributors to the local control of T-helper (Th)2-type inflammation in the airways. This review will discuss their relevant structural-functional features and recent evidence supporting the hypothesis that SP-A and SP-D have a role in regulation of allergic airway sensitization.
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Affiliation(s)
- Angela Haczku
- Pulmonary, Allergy and Critical Care Division, Department of Medicine, University of Pennsylvania School of Medicine, 421 Curie Boulevard, BRB II/III #840, Philadelphia, 19104-6061, USA.
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43
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Edelson BT, Stricker TP, Li Z, Dickeson SK, Shepherd VL, Santoro SA, Zutter MM. Novel collectin/C1q receptor mediates mast cell activation and innate immunity. Blood 2005; 107:143-50. [PMID: 16166590 PMCID: PMC1895357 DOI: 10.1182/blood-2005-06-2218] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Mast cells play a critical role in innate immunity, allergy, and autoimmune diseases. The receptor/ligand interactions that mediate mast cell activation are poorly defined. The alpha2beta1 integrin, a receptor for collagens, laminins, decorin, E-cadherin, matrix metalloproteinase-1 (MMP-1), endorepellin, and several viruses, has been implicated in normal developmental, inflammatory, and oncogenic processes. We recently reported that alpha2 integrin subunit-deficient mice exhibited markedly diminished neutrophil and IL-6 responses during Listeria monocytogenes- and zymosan-induced peritonitis. Peritoneal mast cells require alpha2beta1 integrin expression for activation in response to pathogens, yet the ligand and molecular mechanisms by which the alpha2beta1 integrin induces activation and cytokine secretion remain unknown. We now report that the alpha2beta1 integrin is a novel receptor for multiple collectins and the C1q complement protein. We demonstrate that the alpha2beta1 integrin provides a costimulatory function required for mast cell activation and cytokine secretion. This finding suggests that the alpha2beta1 integrin is not only important for innate immunity but may serve as a critical target for the regulation of autoimmune/allergic disorders.
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Affiliation(s)
- Brian T Edelson
- Department of Pathology, Washington University School of Medicine, St Louis, MO, USA
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Lokitz ML, Zhang W, Bashir M, Sullivan KE, Ang G, Kwon EJ, Lin JH, Werth VP. Ultraviolet-B recruits mannose-binding lectin into skin from non-cutaneous sources. J Invest Dermatol 2005; 125:166-73. [PMID: 15982317 PMCID: PMC11016314 DOI: 10.1111/j.0022-202x.2005.23794.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Mannose-binding lectin (MBL) is an integral part of the innate immune system and functions as an opsonin by binding to pathogens and certain apoptotic cells to promote their uptake by phagocytes. We recently identified an association of low-producing MBL polymorphisms with adult dermatomyositis (DM). Our model is that MBL deficiency leads to a defect in the clearance of apoptotic debris in the skin, thereby predisposing to photosensitive autoimmune disease. In this study, we sought to determine whether MBL binds within the epidermis, and to determine its source, and potential function of this binding. We demonstrated that the MBL is present in irradiated, but not in non-irradiated skin, and in irradiated skin it is bound to apoptotic keratinocytes (KC). We found that MBL is not made by KC, showing indirectly that it comes from an exogenous source, despite the fact that other complement components are made by KC and upregulated by ultraviolet irradiation. Finally, we demonstrated that non-KC-derived MBL bound to apoptotic KC in vitro and increased the uptake of these cells by dendritic cells. We hypothesize that MBL may facilitate non-inflammatory clearance of apoptotic debris in patients with photosensitive forms of DM.
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Affiliation(s)
- Michele L. Lokitz
- Department of Dermatology, University of Pennsylvania, Pennsylvania, USA
| | - Wei Zhang
- Department of Dermatology, University of Pennsylvania, Pennsylvania, USA
| | - Muhammad Bashir
- Department of Dermatology, University of Pennsylvania, Pennsylvania, USA
| | | | - Gina Ang
- Department of Dermatology, University of Pennsylvania, Pennsylvania, USA
| | - Eun Ji Kwon
- Department of Dermatology, University of Pennsylvania, Pennsylvania, USA
| | - Julie H. Lin
- Department of Dermatology, University of Pennsylvania, Pennsylvania, USA
| | - Victoria P. Werth
- Department of Dermatology, University of Pennsylvania, Pennsylvania, USA
- Philadelphia V.A. Hospital, Philadelphia, Pennsylvania, USA
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Zhang M, Bohlson SS, Dy M, Tenner AJ. Modulated interaction of the ERM protein, moesin, with CD93. Immunology 2005; 115:63-73. [PMID: 15819698 PMCID: PMC1782122 DOI: 10.1111/j.1365-2567.2005.02120.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
Abstract
CD93 is a cell-surface glycoprotein that has been shown to influence defence collagen-enhanced Fc-receptor or CR1-mediated phagocytosis of suboptimally opsonized targets in vitro, and CD93-deficient mice are defective in the clearance of apoptotic cells in vivo. To investigate the mechanism of CD93 modulation of phagocytic activity, GST fusion proteins containing the 47 amino acid intracellular domain (GST-Cyto), or various mutants of the intracellular domain of CD93, were constructed and used to identify intracellular CD93-binding molecules. The intracellular protein moesin, well characterized for its role in linking transmembrane proteins to the cytoskeleton and in cytoskeletal remodelling, bound to GST-Cyto when either cell lysates or recombinant moesin were used as a source of interacting molecules. An association of moesin with CD93 within intact cells was confirmed by co-capping moesin with CD93 in human monocytes. The moesin-binding site on CD93 mapped to the first four positively charged amino acids in the juxtamembrane region of the CD93 cytoplasmic tail. Interestingly, deletion of the last 11 amino acids from the C terminus of CD93 (GST-Cyto-C11) dramatically increased moesin binding to the cytoplasmic tail of CD93 in the cell lysate assay, but not when the binding of purified recombinant moesin was assessed. Furthermore, moesin binding to CD93 was enhanced by the addition of phosphatidylinositol 4,5-bisphosphate (PIP(2)). Taken together, these data suggest that the interaction of moesin with the CD93 cytoplasmic domain is modulated by binding of other intracellular molecules to the C11 region and implies that a PIP(2) signalling pathway is involved in CD93 function.
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Affiliation(s)
- Mingyu Zhang
- Department of Molecular Biology and Biochemistry, Center for Immunology, University of California, Irvine, CA 92697, USA
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Ambrosi M, Cameron NR, Davis BG. Lectins: tools for the molecular understanding of the glycocode. Org Biomol Chem 2005; 3:1593-608. [PMID: 15858635 DOI: 10.1039/b414350g] [Citation(s) in RCA: 363] [Impact Index Per Article: 19.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Recent progress in glycobiology has revealed that cell surface oligosaccharides play an essential role in recognition events. More precisely, these saccharides may be complexed by lectins, carbohydrate-binding proteins other than enzymes and antibodies, able to recognise sugars in a highly specific manner. The ubiquity of lectin-carbohydrate interactions opens enormous potential for their exploitation in medicine. Therefore, extraordinary effort is made into the identification of new lectins as well as into the achievement of a deep understanding of their functions and of the precise mechanism of their association with specific ligands. In this review, a summary of the main features of lectins, particularly those found in legumes, will be presented with a focus on the mechanism of carbohydrate-binding. An overview of lectin-carbohydrate interactions will also be given, together with an insight into their energetics. In addition, therapeutic applications of lectins will be discussed.
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Affiliation(s)
- Moira Ambrosi
- Department of Chemistry, University of Durham, South Road, Durham, UKDH1 3LE
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Uemura K, Yamamoto H, Nakagawa T, Nakamura K, Kawasaki N, Oka S, Ma BY, Kawasaki T. Superoxide production from human polymorphonuclear leukocytes by human mannan-binding protein (MBP). Glycoconj J 2005; 21:79-84. [PMID: 15467404 DOI: 10.1023/b:glyc.0000043753.11090.88] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Mannan-binding protein (MBP) is a Ca(2+)-dependent mammalian lectin that plays an important role in innate immunity. In this study, we found that ligand-bound MBP stimulates polymorphonuclear leukocytes (PMN) to induce cell aggregation and superoxide production. The biological response of PMN to ligand-bound MBP was dose- and time-dependent. The PMN aggregation and superoxide production induced by ligand-bound MBP was blocked completely by pertussis toxin, and partially blocked by a platelet activation factor receptor antagonist, TCV-309. These findings suggest that the ligand-bound MBP stimulates PMN through a putative MBP receptor(s) on PMN.
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Affiliation(s)
- Kazuhide Uemura
- Department of Biological Chemistry, Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyo-ku, Kyoto 606-8501 Japan
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Jack DL, Lee ME, Turner MW, Klein NJ, Read RC. Mannose-binding lectin enhances phagocytosis and killing of Neisseria meningitidis by human macrophages. J Leukoc Biol 2004; 77:328-36. [PMID: 15569696 DOI: 10.1189/jlb.0604342] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Deficiency of mannose-binding lectin (MBL) is probably the most common human immunodeficiency and is associated with an increased risk of mucosally acquired infections including meningococcal disease. Tissue macrophages are an important component of mucosal defense, and so we determined the effect of MBL on uptake of meningococci by human monocyte-derived macrophages. Opsonization with MBL significantly increased the capture and doubled the amount of internalization of Neisseria meningitidis. Inhibition of f-actin polymerization indicated that MBL exerted this effect by a dose-dependent acceleration of uptake into phagosomes, which was maximal within the normal physiological concentration of MBL (1.5 microg/ml) and was independent of scavenger receptors. MBL accelerated the acquisition and subsequent loss of the early endosome marker, early endosomal antigen-1, and enhanced the acquisition of the late endosomal marker, lysosome-associated membrane protein-1. MBL reduced the survival of meningococci within macrophages by more than half, despite the increased uptake of organisms, and significantly reduced the number of viable extracellular bacteria by 80%. We conclude that MBL is a dependent opsonin able to accelerate microbial uptake and killing. These results suggest that MBL could modify disease susceptibility by modulating macrophage interactions with mucosal organisms at the site of initial acquisition.
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Affiliation(s)
- Dominic L Jack
- University of Sheffield Medical School, Beech Hill Road, Sheffield, UK, S10 2RX.
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Bohlson SS, Zhang M, Ortiz CE, Tenner AJ. CD93 interacts with the PDZ domain-containing adaptor protein GIPC: implications in the modulation of phagocytosis. J Leukoc Biol 2004; 77:80-9. [PMID: 15459234 DOI: 10.1189/jlb.0504305] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
CD93 was originally identified as a myeloid cell-surface marker and subsequently associated with an ability to modulate phagocytosis of suboptimally opsonized immunoglobulin G and complement particles in vitro. Recent studies using mice deficient in CD93 have demonstrated that this molecule modulates phagocytosis of apoptotic cells in vivo. To investigate signal transduction mechanisms mediated by CD93, CD93 cytoplasmic tail (CYTO)-binding proteins were identified in a yeast two-hybrid screen. Fifteen of 34 positive clones contained a splice variant or a partial cDNA encoding GIPC, a PSD-95/Dlg/ZO-1 (PDZ) domain-containing protein, shown previously to regulate cytoskeletal dynamics. A single clone of the N-terminal kinase-like protein p105 and an uncharacterized stem cell transcript also showed specificity for binding to the CYTO by yeast two-hybrid. Using the yeast two-hybrid system and an in vitro glutathione S-transferase fusion protein-binding assay, the binding of GIPC to the CYTO was shown to involve a newly identified class I PDZ-binding domain in the CD93 carboxyl terminus. Four positively charged amino acids in the juxtamembrane domain of CD93 were shown to be critical in stabilizing these interactions. Treatment of human monocytes with a cell-permeable peptide encoding the C-terminal 11 amino acids of CD93 resulted in an enhancement of phagocytosis, supporting the hypothesis that this protein-protein interaction domain is involved in the modulation of phagocytosis. These protein interactions may participate as molecular switches in modulating cellular phagocytic activity.
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Affiliation(s)
- Suzanne S Bohlson
- Department of Molecular Biology and Biochemistry, University of California, Irvine, CA 92697, USA.
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Saevarsdottir S, Vikingsdottir T, Valdimarsson H. The potential role of mannan-binding lectin in the clearance of self-components including immune complexes. Scand J Immunol 2004; 60:23-9. [PMID: 15238070 DOI: 10.1111/j.0300-9475.2004.01437.x] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Mannan-binding lectin (MBL) is a pattern recognition receptor in the innate immune system. It recognizes certain sugar residues arranged in a pattern that enables MBL to bind with sufficient strength. Such sugar patterns are common on the surface of many microorganisms, and MBL has therefore been considered to be an agent that can discriminate between self and nonself. There is, however, increasing evidence supporting that MBL, like many membrane-bound C-type lectin-like receptors, also helps to dispose of various outworn or abnormal body components. Most self-components are protected with sialic acid or galactose that disrupt the pattern of the sugars that MBL can bind, but MBL may be significantly involved in the elimination of self-components that have lost these protective terminal residues. The role of MBL in the clearance of invading pathogens has previously been thoroughly reviewed. Here, we review some findings that support the notion that MBL may contribute to noninflammatory removal of immune complexes and abnormal cells by the reticuloendothelial system. Defects in this clearance mechanism may cause an accumulation of potentially dangerous self-components, thereby increasing the likelihood of chronic inflammation and autoimmunity.
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Affiliation(s)
- S Saevarsdottir
- Department of Immunology, Landspitali-University Hospital, Hringbraut, 101 Reyjavik, Iceland
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